1. Field of the Invention
This invention relates to rubber compositions, more particularly to such a rubber composition which is highly stable in its application under elevated temperature conditions.
2. Prior Art
In order to prevent thermal deterioration of rubber, it has been proposed to use various aging inhibitors such as for example hindered phenol and amines which are effective in capturing free radicals emanating from broken or dissociated molecules at an initial stage of deterioration. More specifically, such radicals are captured by H in the phenolic OH or in amino NH of the respective inhibitor. However, such conventional aging inhibitors are susceptible to volatilization at high temperature and hence their ability would decline during ordinary molding and under severe temperature or shearing conditions. Speedier production of molded articles from rubber materials by extrusion, rolling and profiling is nowadays essential to cope with ever increasing demand in many industrial sectors. This may be achieved literally by increasing the molding temperature and at the same time the shearing speed, but this would give rise to thermal deterioration of the material.
At nuclear power plants, it is mandatory to provide proper measures for holding the various rubber component parts harmless against the influence of irradiation with for example X-rays or ultraviolet rays.